Gearbox oil viscocity

[hornmeister2000]

Just had my g/box oil changed by a garage and noticed they filled it with gearbox oil rather than the 10W40 recommended in the handbook. Is this a problem?

[Jack]

I think gearbox oil may be a little too viscous (thick!) but the only outcome would be excess drag on the gears (perhaps increased fuel consumption and load on the engine - but not much!) and also gearchange action.

I know that Rover altered the requirements of oil in SD1 manual 'boxes because the initial recommendation was too thick and women were complaining about how hard it was to change gear! Or at least, that's what I've heard.

If you can live with it I would not worry too much. No doubt somebody will say otherwise now for a very good reason and I'll look stupid! :p

[hornmeister2000]

Well I'm about to go 4000 miles in it so maybe I'll get it changed again. A mechanic once told me it wasn't possible to change it - is that true? Is it a DIY job? Any tips?

Thanks in advance...

[SimonR]

Yeah, it's very easy, especially the second time you do it!

Take off the passenger side front wheel and the plastic access panel. Locate on the gearbox two allen-type bolt heads. One is on the botom face of the gearbox (drain plug) the other is on the end which is facing you (filler hole). The cross section of the allen key is very large and you'll probaby need to buy one especially, or find someone who has a VW and has done this on their car!

Drain out all the old (but new in this case) oil, replace the drain plug and then fill up with the correct oil until it gets high enough to seep out of the filler hole. Then put the filler plug back in.

Should take less than an hour the first time and then 20 mins the second time you do it.

Can't remember what oil I used last time but it was not 10w40, it was the one listed in the Haynes.

D'oh! The penny's just dropped - Being a diesel your car doesn't have the VW box does it?! Well, that's the precedure for the 1.3 and 1.6 petrol Maestros, I'm sure someone will be along shortly to tell you all about your car!

[Jack]

It's the same for diesels. Probably best to look in the Haynes manual for the engine though 'cos there is a few plugs / nuts in that area and you don't want to undo the wrong ones!

I have to say, if it was my car I'd see how it drives. If it is fine getting into gear (cold days will be worst) then I'd leave it. Let's face it, if gear oil damages a gearbox then something must be wrong.

[MaestroMatt]

The cross section of the allen key is very large and you'll probaby need to buy one especially, or find someone who has a VW and has done this on their car![/B]

Just to qualify this, the chap we borrowed the allen key from used to use it on his Beetle gearbox, so that may or may not help you locate one. It is virtually impossible to manufacture a wrench using, for example, a bolt and a couple of nuts. Well, I couldn't make it work, anyway! It is an incredibly easy job, as F153 says, and made my car a lot quieter. For some reason the Haynes seems to think of it more as a belt-and-braces job (i.e. the kind only attempted by the jobsworth purist) but I can't see why a change of oil wouldn't benefit a gearbox a great deal.

[hornmeister2000]

Just to clarify, it's a 1990 MG EFi, which (I think) has a Honda gearbox? From what you all say, I think the hardest part will be getting the wheel off which KwikFit over-tightened for me!

[Maria]

I seem to remember we got a gearbox plug wrench from the local motor factor type place (Autopep - a Motaquip franchise).

[MaestroMatt]

Actually, now I think of it, Screwfix do this (http://www.screwfix.com/app/sfd/cat/pro.jsp?id=17451&ts=38117) set which - I am fairly certain - contains one of the right size.

[Aussie Montego]

A tip for removing Volkswagen type drain plugs that use an allen key, find a nut (a mini wheel nut for example) and stick that in the hex of the plug and then use a ring spanner to undo the plug. ;)

[E_T_V]

This is all from memory so please check in the handbook but:
VW gearboxes use gearbox oil Hypoid 90 or similar.
Honda gearboxes use normal engine oil. 10w-40 or similar.

Don't use the wrong type or your gearbox will not be adequately protected.

[Ricky]

Hi all,

This is a common problem on the 309 (I had to bring it up again! :giveup: ), the earlier boxes use 10/40 where the later ones use 80/90, I have seen the devastation the wrong oil can do (on a nova of all cars!), and believe you me it is not a pretty sight! There were iron filings everywhere!! 'Twas a shame, cos I was just beginning to like that car.....!

Ricky.